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food. Many species do an enormous amount of damage, while in 

 contrast, some of the most beneficial insects are beetles. In the United 

 States, north of Mexico there are one hundred and nine families and 

 twenty-four thousand species recognized. Over 200,000 species 

 from all parts of the world have been described. 



Some of the families which contain the most destructive species 

 are the leaf beetles, Chrysomelidae ; the long-horned wood-boring 

 beetles, Cerambycidae ; the click beetles, Elateridae; the June 

 beetles, Scarabaeidae ; the metallic wood-boring beetles, Buprestidae; 



Fig. 187. — Alfalfa weevil, Phytonomus porticus. Above, larva ; lower left, 

 pupa; lower right adult. (From Knowlton and Sorensen, permission Utah Agri- 

 cultural Experiment Station.) 



and the weevils, Curculionidae. The following families are, in the 

 main, very beneficial: the tiger beetles, Cicindelidae ; ground 

 beetles, Carabidae ; ladybird beetles, Coccinellidae ; and the carrion 

 beetles, Silphidae. The cotton boll weevil, Anthonomus grandis, and 

 the alfalfa weevil, Phytonomus posticus, have done millions of dollars' 

 worth of damage. Other groups of weevils of which the following 

 are typical do considerable damage : the billbugs, Calendra mormon 

 Chitt. ; Rhynchites hicolor var. cockerelU Pierce ; and Apion pro- 

 dive Lee. (Fig. 188). 



